H Kurita1, A Ohtsuka, H Kobayashi, K Kurashina. 1. Department of Dentistry and Oral Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan.
Abstract
OBJECTIVES: To examine the possible relationship between condylar position and disk displacement in the TMJ. METHODS: Forty-eight joints with no disk displacement (NDD), 84 joints with a reducible displaced disk (RDD) and 99 joints with a permanently displaced disk (PDD) were selected. The positions of the condyle and TMJ disk were calculated from lateral MR images. RESULTS: There were significant differences in condylar position between the joints with NDD and RDD, while there was no difference between those with NDD and PDD (Kruskal-Wallis and post-hoc test, P<0.05). There was also a significant correlation between the position of the condylar and the displaced disk (Spearman's rank correlation, P<0.05). The condyle was located more anteriorly with advancing disk displacement. CONCLUSIONS: We suggest that if the disk displacement is slight, the condyle is displaced posteriorly: as the disk displacement becomes more severe (i.e. more anteriorly displaced), the condyle returns to the concentric position.
OBJECTIVES: To examine the possible relationship between condylar position and disk displacement in the TMJ. METHODS: Forty-eight joints with no disk displacement (NDD), 84 joints with a reducible displaced disk (RDD) and 99 joints with a permanently displaced disk (PDD) were selected. The positions of the condyle and TMJ disk were calculated from lateral MR images. RESULTS: There were significant differences in condylar position between the joints with NDD and RDD, while there was no difference between those with NDD and PDD (Kruskal-Wallis and post-hoc test, P<0.05). There was also a significant correlation between the position of the condylar and the displaced disk (Spearman's rank correlation, P<0.05). The condyle was located more anteriorly with advancing disk displacement. CONCLUSIONS: We suggest that if the disk displacement is slight, the condyle is displaced posteriorly: as the disk displacement becomes more severe (i.e. more anteriorly displaced), the condyle returns to the concentric position.